The present disclosure relates to subject matter contained in Japanese Patent Application No. 11-31050 (filed on Feb. 9, 1999), which is expressly incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a biopsy forceps that is inserted into an instrument-inserting channel of an endoscope to take a piece of tissue for a biopsy specimen from a body cavity.
2. Description of the Prior Art
In general, a biopsy forceps used with an endoscope has a control wire axially movably inserted in a flexible sheath that is removably inserted into an instrument-inserting channel of an endoscope. The control wire is advanced or retracted at a control part connected to the proximal end of the sheath, thereby opening or closing a pair of forceps cups pivotally provided at the distal end of the sheath.
The forceps cups have cutting edges on their outer edges to cut off a small piece of tissue from the mucous membrane or the like in a body cavity. The cut piece of tissue is taken into the forceps cups as a biopsy specimen.
However, it is rare that a piece of tissue can be cut off from the mucous membrane or the like simply by closing the forceps cups. The actual practice is as follows. The forceps cups are closed to bite the mucous membrane, and in this state, a piece of tissue is taken from the mucous membrane in such a manner as to tear it off by pulling the control wire toward the proximal end of the sheath.
Consequently, not only the part of the mucous membrane bitten by the forceps cups but also the surrounding tissue may be damaged, resulting in an unnecessarily large wound. If there is a blood vessel in the part bitten by the forceps cups, the blood vessel may be torn off. This may cause profuse bleeding.
An object of the present invention is to provide a biopsy forceps for an endoscope which is designed to minimize the damage to the tissue around a part of the mucous membrane bitten by a pair of forceps cups, thereby reducing the bleeding from the part subjected to the bioptic operation.
Other objects and advantages of the present invention will become apparent from the following detailed description of illustrated embodiments of the invention.
According to the present invention, there is provided a biopsy forceps for an endoscope that includes a flexible sheath and a control wire axially movably inserted in the sheath. A control part is connected to the proximal end of the sheath. The control wire is advanced or retracted at the control part to open or close a pair of forceps cups pivotally provided at the distal end of the sheath. The sheath is formed from a member that does not twist in at least one direction about an axis thereof. A rotation control member is provided on or near the control part to rotate the sheath about the axis in a direction in which the sheath does not twist.